Remove branch on childNeedsDistributionRecalc

third_party/WebKit/Source/core/dom/Text.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights
  * reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 262 matching lines @@
     return false;
 
   // pre-wrap in SVG never makes layoutObject.
   if (style.whiteSpace() == EWhiteSpace::kPreWrap && parent.isSVG())
     return false;
 
   // pre/pre-wrap/pre-line always make layoutObjects.
   if (style.preserveNewline())
     return true;
 
-  // childNeedsDistributionRecalc() here is rare, only happens JS calling
-  // surroundContents() etc. from DOMNodeInsertedIntoDocument etc.
-  if (document().childNeedsDistributionRecalc())
-    return true;

[rune, 2017/02/06 22:58:52]

It looks like this could still happen, looking at the code.

updateTextLayoutObject() -> shouldUpdateLayoutByReattaching() ->
textLayoutObjectIsNeeded() in Text.cpp looks dubious because it may be triggered
by setting characterdata from a script at a point where
distribution/style/layout is dirty, and textLayoutObjectIsNeeded() seems to be
expected to be called during layout (re-)attachment.

(disclaimer: haven't tested/debugged to confirm this)

-
   // Avoiding creation of a layoutObject for the text node is a non-essential
   // memory optimization.  So to avoid blowing up on very wide DOMs, we limit
   // the number of siblings to visit.
   unsigned maxSiblingsToVisit = 50;
 
   const LayoutObject* prev =
       LayoutTreeBuilderTraversal::previousSiblingLayoutObject(
           *this, maxSiblingsToVisit);
   if (prev && prev->isBR())  // <span><br/> <br/></span>
     return false;
@@ skipping 151 matching lines @@
 
 Text* Text::cloneWithData(const String& data) {
   return create(document(), data);
 }
 
 DEFINE_TRACE(Text) {
   CharacterData::trace(visitor);
 }
 
 }  // namespace blink